This invention relates to machine vision systems and more particularly to machine vision systems that enable the orienting of one remote, movable object with respect to another.
There are many instantances in which one remote object must be positioned or oriented with respect to another while one or both objects are moving at relative speed. For example, a vehicle that is piloted by an on-board or remote operator moving through air, space or water must often orient itself with respect to another stationary or moving object or structure. The goal of such maneuvers may be a docking between objects or parts of the objects, approach or departure of the objects with respect to one another, or xe2x80x9cstation-keepingxe2x80x9d in which one object maintains a regulated orientation with respect to the other. Smaller-scale devices, such as endoscopic probes, may require orientation information as they wind their way into a confined space, such as the interior of a jet engine to inspect for defects or damage.
In certain instances, information about a remote structure or object is obtained by another object using a variety of active tracking techniques that include transmission and receipt of active signals such as radar, sonar, and laser using a dedicated transceiver. Based upon feedback (return of signals) from these active tracking systems, appropriate position and orientation data are obtained for the target object or structure. Using this data, one or both or the objects can be more accurately maneuvered into position for docking or to perform other operations that require the relative position of the two objects to be regulated. The maneuvering of one object with respect to another is often directed by a manual operator acting upon the data provided by the active tracking system. In some instances, fairly sophisticated automated systems enable one or both objects to move with respect to each other in response to the tracking system information. Generally, these active tracking systems require expensive and cumbersome devices, usually employing one or more cumbersome emitters or antennas and associated receivers on one or both objects. Accordingly, complex tracking and homing systems are often deployed only on very expensive equipment and only in limited situations.
It is, therefore an object of this invention to provide a system and method for enabling tracking, homing, docking, guidance and generalized station keeping by a first object with respect to a second object or that is reasonably cost-effective, compact and, therefore, applicable to a variety of situations. This system and method should interface with existing hardware and software and should be operable with relatively conventional computer hardware. This system should enable a high degree of three-dimensional tracking, homing, docking, guidance and station-keeping accuracy to be maintained in a variety of conditions, even where both objects are moving with respect to each other.
This invention overcomes the disadvantages of the prior art by providing a system and method for tracking, homing, docking, guidance, and generally maintaining relative position, by a first object with respect to a second object using a machine vision system and at least one associated camera. A machine vision system interacting with the camera or similar optical sensors on the first object acquires an image of the second object (or a portion thereof based upon trained or preloaded image data of the second object. The system attempts to locate a fiducial, or other prominent feature, within the overall acquired image. This fiducial is a relatively localized and readily identifiable structure on the second objectxe2x80x94for example, a light or group of lights, a fin or a painted spot. The machine vision system, which typically includes commercially available software applications having scale and rotation-invariant pattern recognition capabilities, searches, identifies and analyzes the position of the fiducial or pattern within the acquired image. Based upon analysis of the fiducial, the acquired image is aligned and oriented with respect to the stored xe2x80x9cmodelxe2x80x9d image. Such stored xe2x80x9cmodelxe2x80x9d image can, in fact be substituted for real-time acquired images of objects. This can occur when the object acquires an image of another adjacent object with which it plans to orient itself. The term xe2x80x9cmodel imagexe2x80x9d should, therefore, be taken broadly to include such real-time/on-the-fly images.
The system then continues to acquire further images and, thereby, continuously determines the relative alignment and orientation of the acquired image with respect to the first object""s field of view. In performing its analysis the machine vision system analyzes the scale and orientation of the now-aligned, acquired image. Using scale and angular/rotational data, inherent functionalities of the machine vision system calculate a three-dimensional solution that includes relative position, orientation and range of the second object with respect to the first. Based upon the calculated solution, control surfaces or thrust members on the first object, second object or both can be manipulated either manually, or via an on-board autopilot to bring the first and second objects into a desired positioning with respect to each otherxe2x80x94typically docked or on-station.
In one embodiment, the camera may be present on first object, while the resulting tracking data is fed to the second object, which the first views, to be acted upon by automated or manual controls associated with the second object. In another embodiment, systems and associated cameras may be fitted to and operational upon both the first and second objects. Additional objects, also having systems therein that act independently, or in communication with each other are also contemplated.